I needed to replace the blown stock sub on my '03, and took a few pictures along the way to help anyone else who needs to do this as well.

I tried to focus on the parts that aren't as obvious the first time you do it. A few notes:
- The project took me about 3 hours, because I am was going very slow since I am good at hitting my paint/tint/leather with sharp objects when I rush.
- I have seen some minor differences in the back deck on different 2GS's, but mine is a '03 430 Navi if it matters.
- I am fairly new to CLF, but the best way I found to attach photos puts them at the bottom of the post, so they are numbered to match the basic instructions below.
- The only tools I needed were a flat head screwdriver, hammer, socket wrench and extension with 12mm (for seats) and 10mm (sub) sockets.
- My local dealer wanted roughly $350 for the sub, and $300 to install. I decided to go with stock as it is decent and I didn't want to tackle the custom amp, brackets, etc. others have done, and NPR doesn't need that much bass (yes, i'm old). Oh, and $300 to install a sub seemed crazy to me, so here we go:

1 - Remove the seat by pulling up on the seat next to the red circled clips then pulling forward after those are loose.

2 - The back of the seat has four bolts holding it at the bottom (circled), you do not need to remove the seat belt system, so leave those alone. It is a LOT easier to work around the belts than to remove and reinstall them.

3 - Push up the headrests and pull up the flap to expose the nuts holding the top of the seat to the car.

4 - Now you can pull up slightly and push the seat forward.

5 - These trim pieces come off by getting your finger or screwdriver under the bottom of the front edge, and pulling straight out toward the middle of the car as shown. Keep gently pulling to remove the rest of the panel. This takes a good bit of force to start, but is easy after that. Be patient during reassembly of this part, it can take a few minutes to get back in and lined up.

6 - Next, remove the back deck. On my '03 there are three hooks with plastic covers. You can push off the covers with your fingers (pull up on the front edge farthest from the hole in the cover). Next use your socket to remove these. Then remove the three plastic retainers using a flathead or other flat surface under the deck. The deck is only thin fiberboard, so don't put much stress on hit, keep the stress on the plastic retainer.

7 - This is the black plastic padding behind the seat and above the deck. It is held at the back of the car by similar plastic clips as you just removed up front. I was able to unscrew these part way then use a hammer to gently tap them out from in the trunk.

8 - Gently peel back the plastic cover and padding (it is all one unit) until it starts to go behind the seats where more clips will hold it in place.

9 - Now you can get to the sub. Undo the four bolts holding it in, and use the screwdriver to pry up the connector out of the body (arrow).

10 - Install your new sub, reconnect the amp, TEST IT, then put it all back together!

just did this today the Pillars are the hardest part took my sub out since I havent used it
I added a aftermarket subwoofer setup this year and before that had pioneer head unit installed with no amp so it wasnt being used
took it out to let some more bass come into the car

Brian, why do you have to poop on everyone's post? Just saying...like your a self proclaimed Moderator of 2nd Gen GS...LOL

lol...i dont poop on EVERYONE's post but its annoying as hell to see repetition every day,every week,every month on here.yes it was a good new post for a user but you would think you would look on here before doing this.....i mean our youngest 2ND gen is 5 years old and the oldest is 13 years old, your REALLY think none of us have ever replaced a sub ourselves?

not trying to be a self proclaimed moderator at all.

i like how people complain bout people reposting and then the same people complain when i just tell the OP to search YET when i ask them to search and give them examples and show them how to find things like dave asked i STILL am getting gripped at about it. OP this last post has nothing to do with you so dont take it personally